Automated fluid injection devices, particularly automated needle syringes, have gained wide acceptance by industry and by the scientific and medical communities. This is because these devices are generally capable of dispensing very small, accurately measured quantities of fluid specimens on the order of a few microliters, generally a fractional part of a microliter up to about 50 microliters with high accuracy and precision. Moreover, the advantages offered by modern data gathering techniques, and consequent reduction in operating man power without loss in accuracy make these devices particularly useful in modern industrial establishments.
Typically, in the operation of an automated fluid injection device, septum covered bottles, or vials charged with a fluid specimen, are transported in seratim via a magazine to a station adjacent a probe assembly, a needle of the probe assembly is projected through the septum of a vial and employed as a conduit to convey a portion of the fluid specimen to the barrel of the syringe. The circuit through which the specimen is conducted, and barrel and needle of the syringe are cleaned, purged and a quantity of the fluid specimen is measured out and injected via the needle end of the syringe into the inlet of an analytical instrument, e.g., a G.C. or mass spectrometer.
Whereas these devices have proven admirably satisfactory in sampling and analyzing fluid specimens, viz. gases and liquids, and have replaced much of the earlier used technology for the sampling and analysis of fluid specimens, techniques and methods for the sampling and analysis of solids and semi-solids materials which contain volatiles components lag far behind. Innumerable hours are presently spent in the qualitative and quantitative analysis of solids and semi-solids materials, e.g., soil samples to determine the presence and content of non-solids, or fluids components. Moreover, e.g., tissues, exemplary of which are shrimp, fish, meat and orange peels, and plastics materials, are frequently analyzed for determination of the presence of various volatile, liquid or gas components. Present procedures almost, if not always, invariably require grinding up the solids or semi-solids specimen, washing the solids with a liquid to dissolve out the component for which the analysis is being made, clean up of the solution, and injection of the solution into an analytical instrument. Analysis of this type require a great deal of time, manipulations and close attention by a very skilled technician, or operative. Most want for accuracy, not on small part due to the difficulty of properly grinding up the specimen, but also due to the failure to completely extract with the solvent the component, or components, to be analyzed. There thus exists a need to provide better techniques for the qualitative and quantitative sampling of solids and semi-solids materials for analysis of their non-solids components.